Linux C HMAC-SHA256 (内核态）

需要SHA256算法支持！详情请点击  Linux C sha256算法实现

/*
 * hmac_sha256.h
 */
#include "sha256.h"

#define HMAC_SHA256_DIGEST_LENGTH	32
#define HMAC_SHA256_BLOCK_LENGTH	64

typedef struct _HMAC_SHA256_CTX {
	unsigned char	ipad[HMAC_SHA256_BLOCK_LENGTH];
	unsigned char	opad[HMAC_SHA256_BLOCK_LENGTH];
	SHA256_CTX		shactx;
	unsigned char	key[HMAC_SHA256_BLOCK_LENGTH];
	unsigned int	keylen;
	unsigned int	hashkey;
} HMAC_SHA256_CTX;

void HMAC_SHA256_Init(HMAC_SHA256_CTX *ctx);
void HMAC_SHA256_UpdateKey(HMAC_SHA256_CTX *ctx, const unsigned char *key, unsigned int keylen);
void HMAC_SHA256_EndKey(HMAC_SHA256_CTX *ctx);
void HMAC_SHA256_StartMessage(HMAC_SHA256_CTX *ctx);
void HMAC_SHA256_UpdateMessage(HMAC_SHA256_CTX *ctx, const unsigned char *data, unsigned int datalen);
void HMAC_SHA256_EndMessage(unsigned char *out, HMAC_SHA256_CTX *ctx